1. Field of the Invention
The present invention relates in general to a method and apparatus for recording information used to assist an individual in learning a language ("language learning information") onto a compact disk, and for reproducing the same. More particularly, the present invention is directed to a method and apparatus for recording and reproducing language learning information on/from a compact disk, in which sub-Q data and language learning data are alternately recorded on a portion of the compact disk.
The present invention further relates to a method and apparatus for recording language learning information on a compact disk, in which audio data is recorded and reproduced separately on/from left and right channels of the compact disk, thereby doubling the recording/reproduction capacities of the compact disk.
2. Description of the Related Art
Generally, a compact disk is constructed of a circular plate having a diameter of 12 cm. Typically, the compact disk is recorded at a high density with audio data, and with program data, which is indicative of the various information associated with the recorded audio data. Reproduction of the recorded audio data typically requires at least one hour. The data is reproduced by a pickup device in a non-contact fashion, such that the tracks recorded with the audio data are not abraded. This type of non-contact reproduction prolongs the life of the compact disk.
Since the compact disk is digitally recorded, there is very little, if any, signal degradation. Therefore, such a compact disk will exhibit a high signal-to-noise ratio (S/N ratio) of at least 90 dB, as compared to a conventional circular plate disk. A compact disk is also generally provided with an aluminum reflecting film to cover the portion recorded with the audio data. This guards against external forces and yields a more durable compact disk.
In general terms, a compact disk has three areas in which information is recorded. The three areas include a lead-in area, a general signal area, and a lead-out area. On the general signal area, the general audio data is recorded. On the lead-in area, various program data associated with the audio data recorded on the general signal area is recorded. On the lead-out area, program data indicative of the fact that all information recorded on the compact disk has been reproduced is recorded.
In operation, the program data associated with the audio data recorded on the compact disk is detected from the lead-in area in accordance with a user's selection, and a track position of the associated information is determined according to the detected program data. Then, the pickup device is positioned over the track on which the associated information is recorded, and the information is reproduced. In this manner, a desired one of a plurality of audio data recorded on the general signal area is reproduced.
FIG. 1 illustrates a data recording format of a compact disk as described above. The general signal area is recorded with sub-Q data every 13.3 ms, in addition to the general audio data. The sub-Q data refers to information regarding the audio data which is currently being reproduced. The sub-Q data is contained in 80 bits of information to indicate an address, serial number, index, and the required time regarding the associated audio data. The total required time and other information regarding the audio data are detected from the associated sub-Q data. A compact disk player analyzes the detected information and displays the analyzed result on a display panel, thereby informing the user of the information regarding the audio data currently being reproduced.
The sub-Q data is detected about 75 times per second, while the time information retrieved from the sub-Q data is displayed at a much smaller frequency, on the order of seconds. Thus, about 6000 bits (i.e., 80 bits/group of sub-Q data.times.75 groups/second) of sub-Q data are recorded repeatedly every second. In the end, the compact disk is recorded with a large amount of information that is redundant and/or never used.
As is generally known, compact disks are often used for music. Typically, such music compact disks are recorded in stereo, meaning that the audio data is simultaneously recorded on left and right channels (referred to hereinafter as L and R-channels) of the general signal area of the compact disk.
However, where the compact disk is used for assisting one to learn a language, it need not be recorded in stereo. In this case, the audio data is recorded on only one of the L and R-channels of the general signal area. This results in reduced recording efficiency.